It's been six months since the Sol has been looking for Rhodan but to no avail. Douc Langur and the other three researchers from the Empress of Therm decide to go on a quest to look for their identity. They steal Rhodan's crystal from Alaska and then tell Atlan that the time has come for them to leave. Only Bjo Breiskoll is aware of the plan of the researchers, but he decides to keep this information for himself.

After they are gone, Blo tells Atlan about what happened and explains that he decided to let them go because they can lead the Terrans to Rhodan. To make sure that they would come back, Blo removed a vital piece of their regeneration chamber.

After analyzing the radiations emitted by the crystal, the researchers reach a world where they find a station from the Hulkoos. However, traps laid out by Bardioc kill all the researchers except for Douc Langur. At the same time, Puukhar, the Choolk warlord, is drawn to the planet by his own black crystal but his fleet is decimated by the Hulkoos, and his spaceship crashes on the planet.

The researcher and Puukar put their crystals together and finally, Douc Langur learns about his true identity, which is neither that of a robot nor a human being. But the truth is so hard to admit that he decides to keep it to himself.

The Sol arrives on the planet and retrieves the two survivors. They pick up traces of Rhodan's activator but they are too late, the incarnation has already left.